Combination automatic and pressure drip coffee maker



1951 A. c. wlLcox 2,575,777

COMBINATION AUTOMATIC AND PRESSURE DRIP COFFEE MAKER Filed Dec. 13, 1947 4 Sheets-Sheet l fps gwu m fllberl'C. Wilcox 15 W wag .4;

A. c. WILCOX 2,575,777

COMBINATION AUTOMATIC AND PRESSURE DRIP COFFEE MAKER Nov. 20, 1951 4 Sheets-Sheet 2 Filed Dec. 13, 194'? fllbert 6. Wilcox A. C. WILCOX Nov. 20, 195] COMBINATION AUTOMATIC AND PRESSURE DRIP COFFEE MAKER 4 Sheets-Sheet Filed Dec. 15, 194'? fllberl' L Wilcox Nov. 20, 1951 A. c. WILCOX 2,575,777

COMBINATION AUTOMATIC AND PRESSURE DRIP COFFEE MAKER Filed Dec. 13, 194'? A 4 Sheets-Sheet 4 I: I; /45 a o l l} n F29; grwmvtcm 5 1% T 65 fllberiawilaaw W" 1 Mi 35? $1 .wg'g 166 {66 161 166 Patented Nov. 20, 1951 UNITED STATES PATENT OFFICE COMBINATION AUTOMATIC AND PRESSURE DRIP COFFEE MAKER The invention relates to coffee makers of the type in which the coffee is brewed in an upper container and siphoned by pressure through a tube and into a lower receptacle.

An object of the invention is to provide a coffee maker of this character having a water and coffee container, a heating element in the wall of the same and a beverage receptacle below the heating element with a double siphon tube whereby the liquid is siphoned, under pressure of the steam created by the brewing of the coffee, from the upper container to the lower receptacle.

Another object is to provide such a device in which a conical screen is located around the lower portion of the siphon tube within the upper container.

A further object is to provide a coffee maker of this character in which the brewed coffee is sprayed from the lower end of the siphon tube onto ashell upon which is mounted a bi-metal strip for automatically operating a switch and breaking the circuit to the heating element.

A still further object is to provide a device of this character in which a momentary thumber button is provided for closing the switch to the heating element circuit to start the operation of the coffee maker.

Another object is to provide a coffee maker of this character in which a perforated coffee basket is located below the upper container in position'to receive the heated liquid from the siphon tube.

A further object is to providesuch a coffee maker in which a conical screen surrounds the lower portion of. the double siphon tube within the upper container.

A still further object is to provide a coffee maker of the character referred to in which a well is formed in the bottom ofthe upper container, and a sieve is located at the top of the well.

It is another object of the invention to provide a coffee maker having a heating element below the beverage receptacle for keeping the beverage hot after it has been brewed.

The above objects together with others which will be apparent from the drawings and following description or which may be later referred to, may be attained by constructing. the improved pressure coffee maker in the manner hereinafter described in detail and illustrated in the accompanying drawings in which;

Figure 1 is a side elevation of a coffee maker embodying the invention;

Fig. 2 an enlarged vertical sectional view through one embodiment of the improved pressure coffee maker:

Fig. 3 a section on the line 3- 3, Fig. 2, show ing the circuit and switch for the heating element, and the momentary thumber button for manually closing the switch andthe bi-metal strip for automatically opening the switch;

Fig. 4 a detail sectional view of the switch taken on the line 44, Fig. 2;

Fig. 5 a fragmentary perspective view of the Bakelite housing within which the switch and circuit are located, with adjacent portions of the upper container and lower receptacle;

Fig. 6 an enlarged longitudinal sectional view of the momentary thumber button;

Fig. 7 a vertical sectional view showing the improved pressure coffee maker converted into a drip coffee maker;

Fig. 8 a vertical sectional view of a modified form of the pressure cofiee maker;

Fig. 9 a detail section on the line 9--9, Fig. 8;

Fig. 10 a sectional elevation of the outer tube showing a plurality of filters carried thereby;

Fig, 11 a fragmentary sectional elevation of a further modification; and

Fig. 12 a fragmentary section of the lower portion of the lower receptacle showing a heating element therefor.

The improved coffee maker comprises the lower receptacle [5, an insulated housing It located above the same and an upper container I! mounted upon the insulated housing.

In this form of the invention the upper container I1 is shouldered and reduced midway of its height as indicated at l8, and then further shouldered and reduced just below this point as indicated at I 9.

A band of insulation such as mica indicated at 20 surrounds the reduced lower portion [9 and an electric heating element in the form of a split ring 2| is located around this mica band and surrounded in turn by a second mica band 22.

A tightening belt 23 of steel or the like surrounds the heating unit with the mica insulation on each side clamping this assembly against the outside of the reduced portion 19 of the container.

An asbestos or other heat and cold insulation 24 surrounds the steel tightening belt and the entire heating unit assembly is enclosed by the outer shell 25 which may be of cylindrical shape, the upper end thereof fitting the shouldered portion [8 of the container, an annular inturned flange 26 being formed at the lower end of said outer shell spaced below the heating unit, di cs 2'! and 28 of asbestos or other suitable heat and cold insulation material being supported thereby and interposed between the bottom Wall and the upper container I! and the top of the Bakelite or other insulate-d housing [6.

The siphoning or bleeder tube comprises the inner tube 29 having its upper end internally threaded as at 30 and provided with a peripheral flange '3 f atapoint-spaced fromits lower end and spaced from theinnei" surface of the bottorrr'wall of the container by the gasket 32, the lower end portion of this tube being preferably enlarged in diameter as shown and extended"throughsuitable openings in the bottom wall of the oontai'ner 'thc asbestos discs 2'! and 28 and the top wall of the Bakelite housing it, and is externally screw threaded as indicated at I133;a'lock nut 3 i being threaded thereon against the under surface of the top wall of the Bakelite housing toelamp the same tightly against the asbestos discs 21 and 28 the'bottoni- =w'all of -the upper container.

The outer tube 35 has aninturned-uppen end *3'6 restingmpon the top'0f the inner tube 29 and held clampedthereombythe: lower threads 31: of the stud 38. B'leederholes 39 are formedin-the V upper end portion of the inner tube 29 and the outer tube 35- terminates s'xbo've the flange" 3 l of the inner tube forming 'bleeder' ports-40.

The cover or lid ar-r01 the upper container ii may beiprovided'fwith'the depending flange 42' adapted to 'be received within theuppen-open end "of the containerandis provided with the annular groove it' to'receivethe-round rubber gasket M. "A blee'derport'45 is formed-in the lid M to regulate the timingof thecoiiee flow andto prevent; w'premature siphoning. A knob ipfi Bakelite or 3 other suitable material is connected to-the-top of the lid by means of the stud "fia and set screw'49, a sealing washer fit 'beingpref'erably located between the knob" ---and the top of the-"lid.

The stud 18 has a 'nut portion {5 latits lower endior jthreadi-ng-tupon theupperthreads 52 of similar-"handle EB -inay be provided upon-theupper.

container for manipulating thesame. 7 u A shell; as indicated generally at 51- in l ig.- 2,

is located below-the parts just describedand may comprise the--inverted, eupshaped.- portion 58,

1.. h i a en r l? e u e r ei n he. lower:

threaded end 33p? the innertube, the-flared lower conical portion 59 terminatingin the upturned m e ear 29 i we thebrilvhral flange 6 I; fitting within I the upper open-end of the lower receptacle i5 and within the peripher-x -ho-les Stare formed near the lower closed end of theinner tube29.

The -'plug -in-- terminals "6? and 158' are located through one side ofthe Baklite housing 6. A

conductor 69 leads from'the'terniinalti to the electric light bulb It, which is attached to the top wall of the Bakelite housing l6 a by the U-shape clamping strip 7 i, the conductor 39 being also connected to the terminal 72 of the heating unit 2|.

A conductor 13 connects the light bulb H! to the other terminal 14 of the heating unit which is f conricted by the Casanov '15 with the lower "switch terminal 'lfi. Nconductor' 'i'i 'l'ea ds from y the plug in terminal 68 to the upper switch terminal 18 of the single throw unit switch indicated sen m retl .7 The switch has the arm 86 pivoted as at BI and 15, provided with a switch tripping lever 82 pivoted thereon'asat 83 and provided with the spring 3 Upper and- -lower contact points 85 and 85 upon the switch arm flii are adapted to engage the dpper and lower fixed contacts 8! and 88 when the switch is closed, closing the circuit from the plugin "terminals '61 and saw the heating unit and light'bulb.

a Aelight =casing-89y whichis preferably red in color and formedoiwglass orot'hei suitable transparentor' translucentqnaterial, enclosesand pro- 'tects' the light bulb.

For the purpose i closing theswitch, -amomentary thumberbutton-is provided indicated generallyat 9ll;-and"shown in" detail inEigw-S.

- "ThlS button has a headed stem 9| attached there- -1 to as by the screwthreads-Qh the stem being slid- "ably located through the hollow, threaded" stud 93, which is-located=through asuita-bleeopening '94 in the-Bakelite housing-l6 and'provided-with i -a- I shoulder 95' engaging: the outersi-de of r the Bakelite housing, a nut 96 mountedenpon the threaded stud engaging =the-- inner-- sideof the housing and clamping -the studin position-therein. -A coil spring "91 "is located around the Jheaded hold the button-9l1 111171180lltWaI'dpOSitiOn. When the button Mus-pushed inward it moves: the switch arm-80 from the-dotted linep'osition to -the -=full "line-:--position as Y in Fig;- 7 3, "closing-the r245 switch. r

=An-arcuate7 bi inetal strip -=98- is connec'ted' at one end to the outer side of the-cupportion'fiti ---ofthe=shell as bythestud'orri'vet 99a3nd normally =1ays ina-con-tact with the periphery or the oo cup'portion 58;--as shown in -full 'lines in FigsB.

When the switch is closed the end of the switch tripping lever 82 contacts the free-"endrpo'rtion --of-thebi -metal stripw As the bi-metal-strip is heated it-wi1l spring outward tothe dotted-' 'line "position shown in Fig 3;"tripping the switch lever 82 and opening the switch.

; As 'best shownin Fig3=5 an'indic'ating line r I 00' is providedeuponthe un'der side of the plug- -in terminal projection -w l of the Bakelite'housing 6O 16 anda'-'plurality 'ofcooperatinggraduations 4122 are formed upon the periphery of the flanged p'or- -ftion'6 l-o'f the filter shell. I

The indicating -"l-i-ne l 00* and 'graduatiohs I 02 are =for the purpose? of ad-justing 1 the bi-in'retal. 05 When this indicatingline and thegraduationsare I in the position shownin- Fign 5", the' shoulder I 03 of the bi-metal strip is in properpo'sition -relative to the trippi-ng 'lever 32.

*Wh'enth'e assembly of the' c'offee makeris com- 'p1eted5-the fastening' nut fii'is loosened 'and'the filter sh-ell '51 is turnedeineither direction -bringing the shoulderWM-"orthe bi metalistrip either -closer-'to' or fartherr-away 'iro'm the tripping lever 7.1 The method of fixingthis-" adiustment is to press, the momentary thumber button 90, which puts the switch in the on position and the tripping lever 82 is locked in place. Then turn the shell 51 slowly until the shoulder I03 of the bimetal strip trim the lever 82. Then reverse the position of theshell 51 and move to the desired graduation and tighten the nut 65.

'By this method close calibrations of the bimetal can be set by graduations at almost the precise time wanted for switch tripping when hot water flows to the bi-metal chamber.

The timing of the operation may be controlled by the size of the bleeder port 45. If a small hole is provided the coffee will flow from the upper container shortly after the boiling point is reached, while if a larger hole is provided, the flow of coffee from the upper container will be prolonged after the boiling point. Any conventional means may be provided for adjusting this size ofthe bleeder port so that light or strong coffee can be made, or the bleeder port may be formed of pre-determined size at the factory.

' In the operation of the coffee maker the lid 4| is removed from the upper container and the proper amount of ground coffee and water are placed in the upper container I I, the coffee surrounding the perforate cone 53, and the lid is replaced and clamped in place by means of the studs 48 and 52. I

The momentary thumber button 90 is pressed, moving the switch to closed position, the shoulder I04 of the tripping lever 82 engaging over the edge of the switch housing I I15 holding the switch in closed position. Current thus passes from the plug-in terminals 61 and 68 through the leads above described to the heating unit 2I and the light bulb Ill.

The water heats and as it boils some steam escapes through the bleeder port 45 after which as the steam pressure increases, thebrewed coffee beverage will be forced, by steam pressure in the upper container upon the top of the liquid, through the port 40, up through the outer tube 35, then through the bleeder holes 39 and down through the inner tube 29, and the hot coffee is sprayed under pressure through the holes 66 against the inner walls of the cup portion 58 of the filtershell. The heat is radiated to the bi-metal strip 98 causing it to assume the dotted line position shown in Fig. 3, contacting the switch tripping lever 82 and disengaging the shoulder I 04 thereof from the switch housing I05, permitting the spring 84 to draw the switch arm 80 to the open position shown in dotted lines in Fig. 3, breaking the circuitto the heating element and light bulb III.

The insulated unit retains its heat for some considerable time after the switch is opened and the boiling action will continue until all of the brewed coffee is extracted from the upper container II, the coffee being siphoned through the tubes and 29 and passing down through the filter cloth 63 which catches the finer particles of coffee that the perforate cone 53 has failed to catch in the upper container, the bulb pulp of the cofiee remaining in the bottom portion of the upper container around the cone 53.

In order to make a second brew of coffee immediately after the first, cold water is run into the shell 51 which immediately cools the bi-metal strip 98 so that it will move back to the full line position shown in Fig. 3. The second brew of coffee may then be made in the same manner as above described.

The asbestos discs 21 and 28 prevent heat radiation from the upper container II to the Bakelite housing I B, preventing any substantial amount of heat from radiating into the bi-metal chamber, making it compulsory that the device operate only when hot water is received from the upper container I'I into the shell 5'! and prevents any operation of the bi-metal strip by radiated heat from the heating unit.

In Fig. 7 is shown the manner in which the improved automatic pressure coffee maker may be operated as an automatic drip coffee maker. For this purpose the straining cone 53 is removed from the upper container I1 and the shell 51 may be replaced by the shell 51a shown in Fig. 7.

This shell has the cup portion 58a, similar to the cup portion of the shell 51, which is attached to the lower threaded end 33 of the inner tube in the same manner as above described and has a bi-metal strip 98a of the same construction as the bi-metal strip 98.

The horizontal flange 59a is provided at the bottom of the cup portion 58a, having the upstanding peripheral flange I06 provided with studs ID! for engaging the bayonet slots I08 upon the perforate coffee basket I09, whereby the bead III! of the coffee basket will fit closely against the shoulder III of the shell. The coffee basket has one or more bleeder ports II2 in its upper portion and its bottom wall is perforated as shown at II2a.

A filter paper may be placed in the bottom of the coffee basket and the proper amount of coffee placed therein and the coffee basket attached by the bayonet lock to the shell. The proper amount of water is then placed in the upper container I1 and the lid 4I fastened .in place and the momentary thumber button is pressed operating the switch to close the circuit in the manner above described for making coffee under pressure. p

The boiling clear water is siphoned through the tubes 35 and 29 in the manner above described, the water spraying from the lower bleeder holes 66 of the inner tube against the walls of the cupped portion 58a of the shell and flowing through the coffee in the coffee basket and dripping into the lower receptacle I5. The automatic operation of the switch through the actionfof the bi-metal strip will be the same as above described.

In Fig. 8 is shown a modification of the pressure coffee maker. The lower receptacle I5 may be the same as shown in Figs. 2 and 7 and the upper container comprises an inner shell I I 3 and an outer shell H4. The inner shell has a half round bead H5 at its upper end and the lower portion is shouldered as at II6 and reduced as at I I1 and again shouldered at H8 and reduced at II9 forming a well I20 in the bottom thereof.

The reduced portion II! of the container is surrounded with an insulated heating unit, the same as shown in Figs. 2 and 7, and the same reference numerals are applied thereto, the heating unit being enclosed between the inner and outer shells of the upper container.

The upper end of the outer shell II4 engages the half round bead H5 of the inner shell and the lower end of the outer shell has the inturned flange I2I supporting the heat and cold insulation I22, such as asbestos, covering the bottom of the inner shell and insulating the same from the Bakelite housing I6 which may be of the same construction as shown in Figs. 2 and 7.

A knob I23, which may be oblong in shape, although it may be of other shapes, is connected tdthe 4 top .of: the lid i.I 24, aswbyn the. i screws: I25 which also rsecure 1=the cover I2 6' upon::the knob. This'knob has za chamber I21 therein :and. is shouldered Jat *each side viaszindicated ;at I28 to support: opposites-endsx-of a .bi-,-metal-. strip I29, the ends thereofzresting loosely upontheshoul tiers-T128, a clearance being provided. between thersame and ::the cover 1260f the knobisothat the bi-metal is perfectly :free and flexible;

A central-'outlet'passage I3ilis formedthrough the *lower :portion of the knob' I23, Within the threade'dythimble I3I, and a lock-bushing vI32 isthreaded thereon and .providedwith: a 'depende ingzproj'ec'tioni 33 and with small. openings I34 and preierablya-fine sieve :.I35to prevent. grains of coffee from: getting; into: the passage I 36 and uponithe ballvalve seat I36 formed at thelupper endthreof to seat the ball. I31, which is shown attachedcto the centralvportion'. of the bi metal strip129 asqat I38; I

It should be understood that this is a showing ofwone specific embodiment andhthat if desired the bi-metalstrip may be connectedat one end to onesidecf the knob and the. ball attached to'the freeendof the bi-metal strip. A steam whistle I39 'is located upon the cover I26 of the knobg Y The lid I24 is adapted to be tightly-fastened upon the inner shell M3 by means of bayonet slots I48 and studs I4I- to provide a tight fit between the upper container and the lid by means of theround'rubbergasket I42. The siphoningor bleeder tube includes the inner'tube 29a; having its upper end open, and havingaperipheral flange 3Ia spaced from its lowei'gend;fa.gasket 3211 being located between saidffiange and the bottom wall of the, inner shell. I I 3... The lower portion of this tube is prefera'bly enlarged in diameter as, shown and extended-through suitable openings in the bottom 'wall vof the container, the asbestos. I 22landthe top walljof the. Bakelite housing I6, and is ex? terna-lly',-.threaded,as at 33a, alock nut 3.4a being threaded thereon against the under surface of the top wall of the Bakelite housing to clamp the same tightly ,against the asbestos ,l22. andtthe bottom 7 wallof the upper container.

Aifiat very finefilter screen I43 is fixed tothe lower end of theouter. tube34a; and rests upon the shoulder IIB of the inner shell, coveringthe reservoir I20.- Theup-perrend of. the tube 35 is closed, aswindicated- 3112444, andspaced slightly above the endof the inner tube 29a.

.Graduations m ybe placed upon the exterior 'ofr-zthe tube 55a; asuindicatediat I45, to indicate the Qnumberof cups .01 water to be placed initheg upperziccntainer." If desired a-pluralityi of filter" sieves may-be rigidlvconnectedto the lower end portion of the outer tube 34a, as showninFig. 10, comprising the lower filter sieve I43 as shown in Fig. -8, and for fu'rther'refinement of coffee -or elimination of sediment, a filter cloth I46 is placed Ilis locatedllover therbottomcofithe inverted h cup. portion I49 iandriheld imposition: as bythe stud I52; V r o The extension 1331s providedxrsozthat. ground coffee is placed in the .ruppe'r container before the tube'35a'zcarrying the sieve 143,;isp1acedinzthe upper container, theltube wouldset: so. high: that the upper end of'it would contact thelextension I33,:.prev.enting closing of. the lid by. the bayonet lock. This insuresno clogging bycoifee. ofnthe cofiee maker; v .u

The desiredi amount 'ofccoflee. is placedtimthe upper .containensuponzthe filter sieve J 43 ,iand the proper "amount of :water placed 'inzthe upper container. The lid I24'is; placed imposition and locked tightly by means of the, bayonet locks. compressing the rubber. gasket I42 withincthe. bead I I5... The ,momentary lthumber buttonzls. pressed;c-losing the circuit to the heatingunit and the; heatv :willtravel 1 up Y to the space I53: between theinner and'outer shells of the upperecontainen which will be helpful in heatingzthe. water; p

The bi-metal stripi 29, in t the, chamber within the knob, I23,is straight at this time as indicated bydottedlines in Fig. 8sothat the ball, I3! is raised from the seat I36. This tbi-metalzstripais of such thickness that it will not bend :to' close the port I30 untilthere is a considerable-amount of live steam flowing,v I I Different timing for emptying of, the uppercone tainer may be had by varying the thickness ofrthe bi-metalst'ripl29. 'Afterthe coffee boils the-bis metal strip IZl-becomes active as steam is ad? mitted to the. chamber I28 and contacts the same and the bi-metal strip will benddow-n to thefull line position shown in Fig. 8 sothat the ball I31 seats upon theseat; I36: closing the passage-J30,- the ends of the bi-metal strip flexing up to cone tactwith the cover I26 of the knob so-that pressure is exerted upon the ball I31 holding the ball tightly closed. I V V p The trapped steam pressure the upp rrcone.

tainer is now exerteduponthe top ofthe boiling water and coffee in the upper container-1 which flows through the retarding filter I43 mm; the I unobstructed reservoir I23 and; is forced --up through :the outer tube fiat-and downthroughthe inner tube 29a,.bein g sprayed through the bleeder ports 65a. upon the inside of the cup portion I49 of. the shell I 48 operating the bimetal strip BBb and the switch.- in the manner a above described in detail withreference tothe form of .th'invene tion shown in. Fig.2. v

If for any reason the. steam pressurelwou-ldbeexcessive the bi-metal strip I29 is of such thick,- ness-that when such, pressure is; exerted: on-zthe ballv check uvalve,v I31 it .acts as a vpop valve for safety. a j

The steam escaping from the upper container during this operation causes the whistle toblow but as soon as the escapingsteam becomes active on the bi-metal I29 theballcheck valve thereon drops into the sea and closes'ofi the escape-oi steamv at which time the Whistle; stops zbldwine v and the entire pressure isthen exerted on the top; of. the cofiee and water inetherupperr-container andeinpties the same-in aiew seconds into thelower receptacle I .5 so that the vhousewife will know that Vwhenthe whistle stops blowing "the coiiee willbe ready to, serve in a very few seconds.

.When: coffee flows-out ofthe tube 29a the baflle plate I retards the hot coffee :andpermitsa flow of-itthroughthe-openings I5I aIldSIlCh'IG-L tardin-gi action causes the-bi-metalv strip; 981) to act quickerlrom the tra ped-steam and coffee above the baflie plate. g

Where the plural filter sieve arrangement is used, as shown in Fig. 10, when pressure starts to force the coffee out of the upper container, the ground coffee bunches on top of the coarse sieve I41 to such an extent so that it acts as a filter.

' Then the coarse sieve catches the large grains of cofiee and the filter cloth I46 catches the remainder of the fine sediments making a clear cofiee beverage.

When coffee has been brewed and passed to the lower receptacle I5, the lid is removed from the upper container and the upper container and Bakelite housing are removed from the lower receptacle, the lid being placed on the lower receptacle which is used as a pot to serve the coffee.

The outer tube 35d may be graspedby the thumb and forefinger and lifted out of the upper container removing most, if not all, of the ground coffee and the upper container ma be easily rinsed. The sieve acts a scoop for lifting the grains of coffee out of the upper container; 7 In Fig. 11 is shownanother modification, the upper container I'm having a half round bead IIa at its upper end. The lower portion of the container I'Ia is reduced as at I 52 and shouldered as at I53 and further reduced as at I54 forming a reservoir I55 to be covered by the sieve I43a which is fixed upon the outer tube 35a.

The Bakelite housing l6a has a partition Wall I56 intermediate its upper and lower ends and encloses the ring heating unit I51, which is substituted for the ring heating unit as above described in connection with the other forms of the invention. The sieve 3a is set far from the lower end of the tube 35a and rests upon the shoulder I53 of the upper container.

Using the ring heating unit requires additional heat insulation I58 in the upper cavity I59 of the Bakelite housing to prevent premature operation of the bi-metal strip in the switch cavity I 60 thereof. The same switch mechanism and bimetal strip as shown in any of the forms of the invention above described, may be located within the cavity I60 of the Bakelite housing and theother parts of the cofiee maker may be of any other form above described.

With this construction the boiling action takes place above the sieve MM and there is no boiling action within the reservoir I55. This prevents trapped water and steam under the sieve from percolating up the tube and causing premature emptying of the upper container before the proper time, that is the boiling action has to take place and the steam has to pas out through the knob at which time the bi-metal becomes active blocking oil? the bleeder port with the check valve in the knob. Tea may be brewed in any of these forms of coffee maker in the same manner as above described for the brewing of coflee.

As shown in Fig. 12, means may be provided uponthe bottom of the lower receptacle I5, of any of the forms of the invention, to keep the brewed coffee beverage hot. This means is shown as a conventional electric heatin unit indicated generally at IBI, located upon the under side of the bottom wall I62 of the receptacle and connected thereto by any conventional means, as indicated at I63. Plug-in terminals I 64 are connected to the heating unit and surrounded by the usual guard I65, and in order to hold the heating unit face upon which the coffee maker is placed, feet I66 are provided thereon.

I claim:

1. An automatic pressure coffee maker com- 1'0 spaced above the table or other supporting surprising an upper container, a cover therefor, a double bleeder tube comprising an inner tube extending from a point near the top of the container through the bottom thereof and having an opening at its upper end and a laterally disposed opening at its lower end and an outer tube spaced from the inner tube and closed at its upper end and terminating near the bottom of the container, an inverted cup-shape shell surrounding the lower portion of the inner tube, a curved bi-metal strip having one end connected to the shell and normally contacting the exterior of the shell throughout its entire length, a heating unit associated with the container, a circuit to the heating unit, a switch in the circuit located'to be opened by the bi-metal strip and a lower receptacle.

2. An automatic pressure cofiee maker comprising an upper container, a cover therefor, a double bleeder tube comprising an inner'tube ex tending from a point near the top of the container through the bottom thereof and having an opening at its upper end and a laterally disposed opening at its lower end and an outer tube spaced from the inner tube and closed at its upper end and terminating near the bottom of the container, an inverted cup-shape shell surrounding the lower portion of the inner tube, a curved bi-metal strip having one end connected to the shell and normally contacting the exterior of the shell throughout its entirelength, a heating unit associated with the container, a circuit to the heating unit, a light in the circuit, a switch in the circuit located to be opened by the bimetal strip and a lower receptacle.

3. An automatic pressure coffee maker comprising an upper container, a cover therefor, a double bleeder tube comprising an inner tub extending from a point near the top of the container through the bottom thereof and having an open ing at its upper end and a laterally disposed opening at its lower end and an outer tube spaced from the inner tube and closed at its upper end and terminating near the bottom of the container, an inverted cup-shape shell surrounding the lower portion of the inner tube, a curved bi-metal strip having one end connected to the shell and normally contacting the exterior of the shell throughout its entire length, a heating unit associated with the container, a circuit to the heating unit, a switch in the circuit located to be opened by the bi-metal strip and a lower receptacle, and an insulation housing surrounding the circuit and switch and located between the upper container and the lower receptacle.

4. An automatic pressure coffee maker comprising an upper container, a cover therefor, a double bleeder tube comprising an inner tube extending from a point near the top of the container through the bottom thereof and having an opening at its upper end and a laterally disposed opening at its lower end and an outer tube spaced from the inner tube and closed at its upper end and terminating near the bottom of the container, an inverted cup-shape shell surrounding the lower portion of the inner tube, a curved bimetal strip having one end connected to the shell and normally contacting the exterior of the shell throughout its entire length, a heating unit associated with the container, a circuit to the heat ing unit, a switch in the circuit located to be opened by the bi-metal strip, a momentary thumber button for manually closing the switch and a lower receptacle.

5. An automatic pressure coifeemaker comand terminating near the bottom of the con- 7 tainer, an inverted cup-shape shell surrounding the lower portion of the inner tube, a baifle plate closing the bottom of. the shell and having openings therein, a curved bi-metal strip havin one endconnected to .theshell and normally contacting the exterior of the shell throughout its entire length, a heating unit associated with the container, a circuit to the heating unit, aswitch in the circuit located to be opened by the bimetal strip and a lower receptacle.

6. An automatic pressure coffee maker comprising an upper container, a cover therefor, a double bleeder tube comprisin an inner tube ,extending from a point near the top of the container through the bottom thereof and having an opening at its upper end and a laterally disposed opening at its lower end and an outer, tube spaced from the inner tube and closed at its upper end and terminating near the bottom of the container, an inverted cup-shape shell surrounding the lower portion of the inner tube, a curved bimetal strip having one end connected to the shell and normally contacting the exterior of the shell throughout its entire length, a heating unit associated with the container, a circuit to the heatingunit, a switch in the circuit located to be opened-by the bi-metal strip and a lowerreceptacle, an insulation housi g surrounding the circuit and switch and located between the upper container and the lower receptacle, and means upon the inner tube for clamping the upper cone tainer, the insulation-housing and the shell-together.

ALBERT c. WILCOX.

REFERENCES circle The following references are of'record in the file'of this patent:

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' FOREIGN PATENTS Number Country Date 594,221 France June 13,1925 658,126 Germany Mar. 25, 1938 

